Dentin hypersensitivity is a painful condition affecting from 15%-60% of the population. It is caused by the movement of fluid in the dentinal tubules and can be eliminated by occluding these patent tubules. Tooth whitening is a $1.4 billion business in America and is predicted to grow both here and abroad. In this grant we propose a treatment for dentin hypersensitivity coupled with a tooth whitening agent. A nano (300-600 nm0 in length and 50-60 nm in cross section) fluor hydroxyapatite crystals (similar to enamel crystals in shape and composition) and is incorporated into a self etch resin which will bond to both enamel and dentin and can be tinted to be white or tooth colored - a paint on enamel. This novel agent, depending on the curing mechanism will be sold over-the-counter or used as an in-office treatment. We propose in this grant: to measure the bond strength to enamel and dentin; determine the penetration and coverage of tooth surfaces; substantivity; and effect on the hydraulic conductance of dentin by this desensitizing/tooth whitening agent. Three other features of this agent is its ability to release calcium, fluoride and phosphate at low pH which may help in preventing and repairing demineralized enamel and dentin caused by caries. It may also be used to treat and/or prevent erosion of enamel and dentin. It will stimulate dental pulp stem cells to mineralize, therefore forming a pulpal protective barrier in deep cavities. This 5 in1 product, TruEnamel, is unique and offers to consumers and dentists a therapeutic cosmetic with a market of approximately $2 billion.